Sharp X68000 for MiSTer Platform

Work in progress...

What is working:

• FDD images on secondary SD card
• HDD images (SASI only!) on secondary SD card

Issues:

• keyboard in disk emu screen sometimes doesn't work
• config file sometimes gets corrupted after save.
• floppy images mounted as ejected (Nios II source code required to get it fixed)
• Unused real HDD/FDD options should be deleted from menu.
• Reset works only once (probably Nios II FW bug).

Special keys

F11 - switch to diskemu menu.